Enum typewit::TypeCmp

pub enum TypeCmp<L: ?Sized, R: ?Sized> {
    Eq(TypeEq<L, R>),
    Ne(TypeNe<L, R>),
}

The result of comparing two types for equality.

Example

Custom array creation

(this example requires Rust 1.63.0, because of [std::array::from_fn]).

use typewit::{const_marker::Usize, TypeCmp, TypeEq, TypeNe};
 
let empty: [String; 0] = [];
assert_eq!(ArrayMaker::<String, 0>::empty().make(), empty);
 
assert_eq!(ArrayMaker::<u8, 2>::defaulted().make(), [0u8, 0u8]);
 
assert_eq!(ArrayMaker::with(|i| i.pow(2)).make(), [0usize, 1, 4, 9]);
 
 
enum ArrayMaker<T, const LEN: usize> {
    NonEmpty(fn(usize) -> T, TypeNe<[T; LEN], [T; 0]>),
    Empty(TypeEq<[T; LEN], [T; 0]>),
}
 
impl<T, const LEN: usize> ArrayMaker<T, LEN> {
    pub fn make(self) -> [T; LEN] {
        match self {
            ArrayMaker::NonEmpty(func, _) => std::array::from_fn(func),
            ArrayMaker::Empty(te) => te.to_left([]),
        }
    }
 
    pub const fn defaulted() -> Self 
    where
        T: Default
    {
        Self::with(|_| Default::default())
    }
 
    pub const fn with(func: fn(usize) -> T) -> Self {
        match  Usize::<LEN>.equals(Usize::<0>) // : TypeCmp<Usize<LEN>, Usize<0>>
            .project::<ArrayFn<T>>() // : TypeCmp<[T; LEN], [T; 0]>
        {
            TypeCmp::Ne(ne) => ArrayMaker::NonEmpty(func, ne),
            TypeCmp::Eq(eq) => ArrayMaker::Empty(eq),
        }
    }
}
 
impl<T> ArrayMaker<T, 0> {
    pub const fn empty() -> Self {
        Self::Empty(TypeEq::NEW)
    }
}
 
impl<T, const LEN: usize> Copy for ArrayMaker<T, LEN> {}
 
impl<T, const LEN: usize> Clone for ArrayMaker<T, LEN> {
    fn clone(&self) -> Self { *self }
}
 
typewit::inj_type_fn! {
    // Declares `struct ArrayFn`, which implements `InjTypeFn<Usize<LEN>>`:
    // an injective type-level function from `Usize<LEN>` to `[T; LEN]`
    struct ArrayFn<T>;
    impl<const LEN: usize> Usize<LEN> => [T; LEN]
}

Variants

Eq(TypeEq<L, R>)

proof of L == R

Ne(TypeNe<L, R>)

proof of L != R

Implementations

impl<L: ?Sized, R: ?Sized> TypeCmp<L, R>

pub fn with_any() -> Self

where L: Sized + Any, R: Sized + Any,

👎Deprecated: fallout of https://github.com/rust-lang/rust/issues/97156,TypeId::of::<L>() != TypeId::of::<R>() does not imply L != R

Constructs a TypeCmp<L, R> by comparing the L and R types for equality.

Example

use typewit::TypeCmp;
 
let eq: TypeCmp<u8, u8> = TypeCmp::with_any();
assert!(matches!(eq, TypeCmp::Eq(_)));
 
let ne = TypeCmp::<u8, i8>::with_any();
assert!(matches!(ne, TypeCmp::Ne(_)));

pub const fn flip(self) -> TypeCmp<R, L>

Swaps the type arguments of this TypeCmp

Example

use typewit::{TypeCmp, type_ne};
 
const TC: TypeCmp<u8, i8> = TypeCmp::Ne(type_ne!(u8, i8));
 
const TK: TypeCmp<i8, u8> = TC.flip();
 

pub const fn join_left<Q: ?Sized>(self, left: TypeEq<Q, L>) -> TypeCmp<Q, R>

Joins this TypeCmp<L, R> with a TypeEq<Q, L>, producing a TypeCmp<Q, R>.

Example

use typewit::{TypeCmp, TypeEq, type_ne};
 
const TC: TypeCmp<str, [u8]> = type_ne!(str, [u8]).to_cmp();
 
const fn foo<A: ?Sized>(eq: TypeEq<A, str>) {
    let _tc: TypeCmp<A, [u8]> = TC.join_left(eq);
}

pub const fn join_right<Q: ?Sized>(self, right: TypeEq<R, Q>) -> TypeCmp<L, Q>

Joins this TypeCmp<L, R> with a TypeEq<R, Q>, producing a TypeCmp<L, Q>.

Example

use typewit::{TypeCmp, TypeEq, type_ne};
 
const NE: TypeCmp<String, Vec<u8>> = type_ne!(String, Vec<u8>).to_cmp();
 
const fn foo<A>(eq: TypeEq<Vec<u8>, A>) {
    let _ne: TypeCmp<String, A> = NE.join_right(eq);
}

pub const fn eq(self) -> Option<TypeEq<L, R>>

Converts this TypeCmp<L, R> into an Option<TypeEq<L, R>>.

Example

use typewit::{TypeCmp, TypeEq, type_ne};
 
let eq: TypeCmp<u8, u8> = TypeCmp::Eq(TypeEq::NEW);
assert!(matches!(eq.eq(), Some(TypeEq::<u8, u8>{..})));
 
let ne = TypeCmp::Ne(type_ne!(u8, i8));
assert!(matches!(ne.eq(), None::<TypeEq<u8, i8>>));

pub const fn ne(self) -> Option<TypeNe<L, R>>

Converts this TypeCmp<L, R> into an Option<TypeNe<L, R>>.

Example

use typewit::{TypeCmp, TypeEq, TypeNe, type_ne};
 
let eq: TypeCmp<u8, u8> = TypeCmp::Eq(TypeEq::NEW);
assert!(matches!(eq.ne(), None::<TypeNe<u8, u8>>));
 
let ne = TypeCmp::Ne(type_ne!(u8, i8));
assert!(matches!(ne.ne(), Some(TypeNe::<u8, i8>{..})));

pub const fn is_eq(self) -> bool

Returns whether this TypeCmp is a TypeCmp::Eq.

Example

use typewit::{TypeCmp, TypeEq, TypeNe, type_ne};
 
const EQ: TypeCmp<u8, u8> = TypeEq::NEW.to_cmp();
assert_eq!(EQ.is_eq(), true);
 
const NE: TypeCmp<i8, u8> = type_ne!(i8, u8).to_cmp();
assert_eq!(NE.is_eq(), false);

pub const fn is_ne(self) -> bool

Returns whether this TypeCmp is a TypeCmp::Ne.

Example

use typewit::{TypeCmp, TypeEq, TypeNe, type_ne};
 
const EQ: TypeCmp<u8, u8> = TypeEq::NEW.to_cmp();
assert_eq!(EQ.is_ne(), false);
 
const NE: TypeCmp<i8, u8> = type_ne!(i8, u8).to_cmp();
assert_eq!(NE.is_ne(), true);

pub const fn unwrap_eq(self) -> TypeEq<L, R>

Returns the contained TypeEq

Panic

Panics if the contained value is a TypeNe.

Example

use typewit::{TypeCmp, TypeEq};
 
let eq: TypeCmp<u8, u8> = TypeCmp::Eq(TypeEq::NEW);
assert!(matches!(eq.unwrap_eq(), TypeEq::<u8, u8>{..}));

pub const fn unwrap_ne(self) -> TypeNe<L, R>

Returns the contained TypeNe

Panic

Panics if the contained value is a TypeEq.

Example

use typewit::{TypeCmp, TypeNe, type_ne};
 
let ne = TypeCmp::Ne(type_ne!(u8, i8));
assert!(matches!(ne.unwrap_ne(), TypeNe::<u8, i8>{..}));

impl<L, R> TypeCmp<L, R>

pub const fn zip<A>(self, other: A) -> TypeCmp<(L, A::L), (R, A::R)>

where A: BaseTypeWitness,

Combines this TypeCmp<L, R> with a BaseTypeWitness type to produce a TypeCmp<(L, A::L), (R, A::R)>.

Alternative

methods::zip2 is an alternative to this function.

This method always returns TypeCmp, while that function returns TypeNe when any argument is a TypeNe.

Returned variant

This returns either TypeCmp::Eq or TypeCmp::Ne depending on the arguments:

• if all arguments (including self) are TypeEq or TypeCmp::Eq, this returns TypeCmp::Eq
• if any argument (including self) is a TypeNe or TypeCmp::Ne, this returns TypeCmp::Ne

Example

use typewit::{TypeCmp, TypeEq, TypeNe, type_ne};
 
 
const NE: TypeNe<u8, i8> = type_ne!(u8, i8);
const EQ: TypeEq<u16, u16> = TypeEq::NEW;
const TC_NE: TypeCmp<u32, u64> = TypeCmp::Ne(type_ne!(u32, u64));
const TC_EQ: TypeCmp<i64, i64> = TypeCmp::Eq(TypeEq::NEW);
 
assert!(matches!(
    TC_EQ.zip(NE),
    TypeCmp::<(i64, u8), (i64, i8)>::Ne(_),
));
 
assert!(matches!(
    TC_EQ.zip(EQ),
    TypeCmp::<(i64, u16), (i64, u16)>::Eq(_),
));
 
assert!(matches!(
    TC_EQ.zip(TC_EQ),
    TypeCmp::<(i64, i64), (i64, i64)>::Eq(_),
));
 
assert!(matches!(
    TC_EQ.zip(TC_NE),
    TypeCmp::<(i64, u32), (i64, u64)>::Ne(_),
));

pub const fn zip3<A, B>( self, arg0: A, arg1: B, ) -> TypeCmp<(L, A::L, B::L), (R, A::R, B::R)>

where A: BaseTypeWitness, A::L: Sized, A::R: Sized, B: BaseTypeWitness,

Combines this TypeCmp<L, R> with two BaseTypeWitness types to produce a TypeCmp<(L, A::L, B::L), (R, A::R, B::R)>.

Alternative

methods::zip3 is an alternative to this function.

This method always returns TypeCmp, while that function returns TypeNe when any argument is a TypeNe.

Returned variant

This returns either TypeCmp::Eq or TypeCmp::Ne depending on the arguments:

• if all arguments (including self) are TypeEq or TypeCmp::Eq, this returns TypeCmp::Eq
• if any argument (including self) is a TypeNe or TypeCmp::Ne, this returns TypeCmp::Ne

Example

use typewit::{TypeCmp, TypeEq, TypeNe, type_ne};
 
 
const NE: TypeNe<u8, i8> = type_ne!(u8, i8);
const EQ: TypeEq<u16, u16> = TypeEq::NEW;
const TC_NE: TypeCmp<u32, u64> = TypeCmp::Ne(type_ne!(u32, u64));
const TC_EQ: TypeCmp<i64, i64> = TypeCmp::Eq(TypeEq::NEW);
 
assert!(matches!(
    TC_EQ.zip3(EQ, NE),
    TypeCmp::<(i64, u16, u8), (i64, u16, i8)>::Ne(_),
));
 
assert!(matches!(
    TC_EQ.zip3(EQ, TC_EQ),
    TypeCmp::<(i64, u16, i64), (i64, u16, i64)>::Eq(_),
));
 
assert!(matches!(
    TC_EQ.zip3(NE, TC_NE),
    TypeCmp::<(i64, u8, u32), (i64, i8, u64)>::Ne(_),
));

pub const fn zip4<A, B, C>( self, arg0: A, arg1: B, arg2: C, ) -> TypeCmp<(L, A::L, B::L, C::L), (R, A::R, B::R, C::R)>

where A: BaseTypeWitness, A::L: Sized, A::R: Sized, B: BaseTypeWitness, B::L: Sized, B::R: Sized, C: BaseTypeWitness,

Combines this TypeCmp<L, R> with three BaseTypeWitness types to produce a TypeCmp<(L, A::L, B::L, C::L), (R, A::R, B::R, C::R)>.

Alternative

methods::zip4 is an alternative to this function.

This method always returns TypeCmp, while that function returns TypeNe when any argument is a TypeNe.

Returned variant

This returns either TypeCmp::Eq or TypeCmp::Ne depending on the arguments:

• if all arguments (including self) are TypeEq or TypeCmp::Eq, this returns TypeCmp::Eq
• if any argument (including self) is a TypeNe or TypeCmp::Ne, this returns TypeCmp::Ne

Example

use typewit::{TypeCmp, TypeEq, TypeNe, type_ne};
 
 
const NE: TypeNe<u8, i8> = type_ne!(u8, i8);
const EQ: TypeEq<u16, u16> = TypeEq::NEW;
const TC_NE: TypeCmp<u32, u64> = TypeCmp::Ne(type_ne!(u32, u64));
const TC_EQ: TypeCmp<i64, i64> = TypeCmp::Eq(TypeEq::NEW);
 
assert!(matches!(
    TC_EQ.zip4(EQ, NE, TC_NE),
    TypeCmp::<(i64, u16, u8, u32), (i64, u16, i8, u64)>::Ne(_),
));
 
assert!(matches!(
    TC_EQ.zip4(EQ, TC_EQ, EQ),
    TypeCmp::<(i64, u16, i64, u16), (i64, u16, i64, u16)>::Eq(_),
));

impl<L: ?Sized, R: ?Sized> TypeCmp<L, R>

Why InjTypeFn

Both map and project require that the function is injective so that TypeCmp’s arguments don’t change from being equal to unequal or viceversa.

pub const fn map<F>( self: TypeCmp<L, R>, func: F, ) -> TypeCmp<CallInjFn<F, L>, CallInjFn<F, R>>

where F: InjTypeFn<L> + InjTypeFn<R>,

Maps the type arguments of this TypeCmp by using the F injective type-level function.

Use this function over project if you want the type of the passed in function to be inferred.

Example

use typewit::{TypeCmp, TypeEq, TypeNe, inj_type_fn, type_ne};
 
use std::num::Wrapping;
 
 
const EQ: TypeCmp<u8, u8> = TypeEq::NEW.to_cmp();
assert!(matches!(EQ.map(WrappingFn), TypeCmp::<Wrapping<u8>, Wrapping<u8>>::Eq(_)));
 
const NE: TypeCmp<i8, u8> = type_ne!(i8, u8).to_cmp();
assert!(matches!(NE.map(WrappingFn), TypeCmp::<Wrapping<i8>, Wrapping<u8>>::Ne(_)));
 
 
inj_type_fn!{
    struct WrappingFn;
 
    impl<T> T => Wrapping<T>
}

pub const fn project<F>( self: TypeCmp<L, R>, ) -> TypeCmp<CallInjFn<F, L>, CallInjFn<F, R>>

where F: InjTypeFn<L> + InjTypeFn<R>,

Maps the type arguments of this TypeCmp by using the F injective type-level function.

Use this function over map if you want to specify the type of the passed in function explicitly.

Example

use typewit::{TypeCmp, TypeEq, TypeNe, inj_type_fn, type_ne};
 
use std::mem::ManuallyDrop as ManDrop;
 
 
const EQ: TypeCmp<u8, u8> = TypeEq::NEW.to_cmp();
assert!(matches!(EQ.project::<ManDropFn>(), TypeCmp::<ManDrop<u8>, ManDrop<u8>>::Eq(_)));
 
const NE: TypeCmp<i8, u8> = type_ne!(i8, u8).to_cmp();
assert!(matches!(NE.project::<ManDropFn>(), TypeCmp::<ManDrop<i8>, ManDrop<u8>>::Ne(_)));
 
 
inj_type_fn!{
    struct ManDropFn;
 
    impl<T> T => ManDrop<T>
}

pub const fn unmap<F>(self, func: F) -> TypeCmp<UncallFn<F, L>, UncallFn<F, R>>

where F: RevTypeFn<L> + RevTypeFn<R>,

Maps the type arguments of this TypeCmp by using the reversed version of the F type-level function.

Use this function over unproject if you want the type of the passed in function to be inferred.

Example

use typewit::{TypeCmp, TypeEq, TypeNe, inj_type_fn, type_ne};
 
use std::num::Wrapping;
 
 
const EQ: TypeCmp<Wrapping<u8>, Wrapping<u8>> = TypeEq::NEW.to_cmp();
 
assert!(matches!(EQ.unmap(WrappingFn), TypeCmp::<u8, u8>::Eq(_)));
 
const NE: TypeCmp<Wrapping<i8>, Wrapping<u8>> = 
    type_ne!(Wrapping<i8>, Wrapping<u8>).to_cmp();
 
assert!(matches!(NE.unmap(WrappingFn), TypeCmp::<i8, u8>::Ne(_)));
 
 
inj_type_fn!{
    struct WrappingFn;
 
    impl<T> T => Wrapping<T>
}

pub const fn unproject<F>(self) -> TypeCmp<UncallFn<F, L>, UncallFn<F, R>>

where F: RevTypeFn<L> + RevTypeFn<R>,

Maps the type arguments of this TypeCmp by using the reversed version of the F type-level function.

Use this function over unmap if you want to specify the type of the passed in function explicitly.

Example

use typewit::{TypeCmp, TypeEq, TypeNe, inj_type_fn, type_ne};
 
use std::mem::MaybeUninit as MaybeUn;
 
 
const EQ: TypeCmp<MaybeUn<u8>, MaybeUn<u8>> = TypeEq::NEW.to_cmp();
 
assert!(matches!(EQ.unproject::<MaybeUnFn>(), TypeCmp::<u8, u8>::Eq(_)));
 
const NE: TypeCmp<MaybeUn<i8>, MaybeUn<u8>> = 
    type_ne!(MaybeUn<i8>, MaybeUn<u8>).to_cmp();
 
assert!(matches!(NE.unproject::<MaybeUnFn>(), TypeCmp::<i8, u8>::Ne(_)));
 
 
inj_type_fn!{
    struct MaybeUnFn;
 
    impl<T> T => MaybeUn<T>
}

pub const fn in_ref<'a>(self) -> TypeCmp<&'a L, &'a R>

Converts a TypeCmp<L, R> to TypeCmp<&L, &R>

Example

use typewit::{TypeCmp, TypeEq, TypeNe, type_ne};
 
const EQ: TypeCmp<u8, u8> = TypeEq::NEW.to_cmp();
assert!(matches!(EQ.in_ref(), TypeCmp::<&u8, &u8>::Eq(_)));
 
const NE: TypeCmp<i8, u8> = type_ne!(i8, u8).to_cmp();
assert!(matches!(NE.in_ref(), TypeCmp::<&i8, &u8>::Ne(_)));
 

pub fn in_mut<'a>(self) -> TypeCmp<&'a mut L, &'a mut R>

Converts a TypeCmp<L, R> to TypeCmp<&mut L, &mut R>

Constness

This requires either of the "mut_refs" or "const_mut_refs" crate features to be enabled to be a const fn.

Example

use typewit::{TypeCmp, TypeEq, TypeNe, type_ne};
 
const EQ: TypeCmp<u8, u8> = TypeEq::NEW.to_cmp();
assert!(matches!(EQ.in_mut(), TypeCmp::<&mut u8, &mut u8>::Eq(_)));
 
const NE: TypeCmp<i8, u8> = type_ne!(i8, u8).to_cmp();
assert!(matches!(NE.in_mut(), TypeCmp::<&mut i8, &mut u8>::Ne(_)));
 

impl<L, R> TypeCmp<L, R>

pub const fn in_array<O, const UL: usize, const UR: usize>( self, other: O, ) -> TypeCmp<[L; UL], [R; UR]>

where O: BaseTypeWitness<L = Usize<UL>, R = Usize<UR>>,

Combines TypeCmp<L, R> and a O:BaseTypeWitness<L = Usize<UL>, R = Usize<UR>> into TypeCmp<[L; UL], [R; UR]>

Alternative

methods::in_array is an alternative to this function.

This method always returns TypeCmp, while that function returns TypeNe when any argument is a TypeNe.

Returned variant

This returns either TypeCmp::Eq or TypeCmp::Ne depending on the arguments:

• if all arguments (including self) are TypeEq or TypeCmp::Eq, this returns TypeCmp::Eq
• if any argument (including self) is a TypeNe or TypeCmp::Ne, this returns TypeCmp::Ne

Example

Basic

use typewit::{
    const_marker::Usize,
    TypeCmp, TypeEq, TypeNe,
    type_ne,
};
 
let cmp_eq_ty: TypeCmp<i32, i32> = TypeCmp::Eq(TypeEq::NEW);
let cmp_ne_ty: TypeCmp<i64, u64> = TypeCmp::Ne(type_ne!(i64, u64));
 
let eq_len: TypeEq<Usize<0>, Usize<0>> = TypeEq::NEW;
let ne_len: TypeNe<Usize<1>, Usize<2>> = Usize.equals(Usize).unwrap_ne();
let cmp_eq_len: TypeCmp<Usize<3>, Usize<3>> = Usize.equals(Usize);
let cmp_ne_len: TypeCmp<Usize<5>, Usize<8>> = Usize.equals(Usize);
 
assert!(matches!(cmp_eq_ty.in_array(eq_len), TypeCmp::<[i32; 0], [i32; 0]>::Eq(_)));
assert!(matches!(cmp_eq_ty.in_array(ne_len), TypeCmp::<[i32; 1], [i32; 2]>::Ne(_)));
assert!(matches!(cmp_eq_ty.in_array(cmp_eq_len), TypeCmp::<[i32; 3], [i32; 3]>::Eq(_)));
assert!(matches!(cmp_eq_ty.in_array(cmp_ne_len), TypeCmp::<[i32; 5], [i32; 8]>::Ne(_)));
 
assert!(matches!(cmp_ne_ty.in_array(eq_len), TypeCmp::<[i64; 0], [u64; 0]>::Ne(_)));
assert!(matches!(cmp_ne_ty.in_array(ne_len), TypeCmp::<[i64; 1], [u64; 2]>::Ne(_)));
assert!(matches!(cmp_ne_ty.in_array(cmp_eq_len), TypeCmp::<[i64; 3], [u64; 3]>::Ne(_)));
assert!(matches!(cmp_ne_ty.in_array(cmp_ne_len), TypeCmp::<[i64; 5], [u64; 8]>::Ne(_)));

Trait Implementations

impl<L: ?Sized, R: ?Sized> BaseTypeWitness for TypeCmp<L, R>

type L = L

The L type parameter of TypeEq/TypeNe/TypeCmp types.

type R = R

The R type parameter of TypeEq/TypeNe/TypeCmp types.

impl<L: ?Sized, R: ?Sized> Clone for TypeCmp<L, R>

fn clone(&self) -> Self

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<L: ?Sized, R: ?Sized> Debug for TypeCmp<L, R>

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<L: ?Sized, R: ?Sized> Hash for TypeCmp<L, R>

fn hash<H>(&self, state: &mut H)

where H: Hasher,

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl<L: ?Sized, R: ?Sized> Ord for TypeCmp<L, R>

fn cmp(&self, other: &Self) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized + PartialOrd,

Restrict a value to a certain interval.

impl<L: ?Sized, R: ?Sized> PartialEq for TypeCmp<L, R>

fn eq(&self, other: &Self) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl<L: ?Sized, R: ?Sized> PartialOrd for TypeCmp<L, R>

fn partial_cmp(&self, other: &Self) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

fn lt(&self, other: &Rhs) -> bool

This method tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

This method tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

This method tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

This method tests greater than or equal to (for self and other) and is used by the >= operator.

impl<L: ?Sized, R: ?Sized> Copy for TypeCmp<L, R>

impl<L: ?Sized, R: ?Sized> Eq for TypeCmp<L, R>